The effect of calcium lignosulfonate (CLS) on the early hydration characteristics for clinker minerals was investigated. In the presence of CLS and unsufficient gypsum The hydration of A lowered CLS adsorption to form ettrin-gite and the residual CLS in the liquid phase accelerated the solubility of C4AF hydration. As the result unreacted in the liquid phase would be precipitated gelatinously on hydrates and the hydration of could be retarded. But by addition of optimum gypsum into the cement with CLS the presence of in the liquid phase were lowered and hydration would be normallized.

The effect of stress induced phase transformation on matrix dispersed with has been studied. In order to determinate the mechanical properties three composite series containing 1, 3 and 5 mole% were prepared. The starting materials were and which was prepared from the aqueous solution of high purity . and .. Powder mixtures of containing have been prepared by ball-milling with methanol and the samples were formed by isostatic press and sintered at 150 for 2hrs. After sintering. the specimens were polished for mechanical determination. The relative density of sintered specimens were also measured. It was found that the addition of 1, 3mole% to {{{{ { ZrO}_{2 } }} allowed full retention of the tetragonal phase in but partially stabilized zirconia (PSZ) was produced by additions of 5 mole% .The critical stress-intensity factor KIc of (containing 1 mole% ) composite materials increased with increasing content, The maximum value of KIC=7Mn//2 at 20 mole% exhibited about twice that of the The modulus of rupture exhibited a trend similiar to KIC The maximum value of MOR was 580MN/m2. As the amount of Y2O3 increase it was observed that the maximum of KIC and MOR decreased : Additions of 3 mole% allowed the maximum of KIC 6MN//2 MOR 540MN/ at 15 mole% additions of 5 mole% allowed the maximum of KIC 5MN//2 MOR 410MN/ at 10 mole% .

The states of alkali occuring in Portland cement clinker were studied. Potassium was added to raw mixture by there kinds ; , and KOH. In case of and KOH addition the new state of unstable alkali was found when alkakli content is high and content is low in the clinker. Unstable state of highly basic free causes lowering burnability much more than alkali sulfate especially at the early stage of burning. Lowered burnability by became more serious with higher LSF. Unstable free- which is readily soluble with water reacts with gypsum to form $Ca(OH)_2$ and syngenite as soon as water is added. As a results the liberation rate of heat of hydration at the early hydration process(1st peak) was increased.

Synthetic mica was treated with HCl solution and H-type exchange resin to investigate the chemical stability and the ion exchange by measuring the dissolution of chemical components and the exchanged ion. The replacement of ion occurred in contact with HCl solution and H-type ion exchange resin at the surface of Na-TSM particles reached ions at maximum value of 70~80%. ion of octahedral layer became to dissolve from the pH2 solution and th amount of it dissolved in-creased almost proportional to ion concentration from around 0.02N ion equilibrium concentration. The crystalline structure of Na-TSM was destructed by dissolution of Mg2+ ion in cncentrated hydrochloric acid solution and resulted silica gel precipitation.

The effect of calcining temperature ranged from to 110 on sintering characteristics of morphotropic $Pb(Zr_{0.53}Ti_{0.47})O_3 doped with has been investigated. The ratio of sintered grain size to calcined grain size decreased as the calcining temperature increased. The hardness as well as the sintered density of the samples reached a maximum at about 90. The X-ray diffraction pattern of the sintered sample showed both tetragonal and rhombohedral phases. The tetragonal phases intensity increased with the calcining temperature going through a maximum at about 90 while the rhombohedral phase intensity remained uneffected. The both intensity were about the same at 90 The dielectric constant of the sintered samples reached a maximum um while the dielectric dissipation factor showed a minimum at the calcining temperature of about 100

The effect of calcining temperature on planar coupling factor Kp resonance and antiresonance frequency of doped with has been investigated. The calcining temperature ranged from to 110 The calcining temperature affected on antiresonance frequency more strongly than the resonance frequency. Therefore the Kp was almost entirely dependent upon the antiresonance frequency. The p and antiresonance frequency of the sample in creased with the calcining temperature reaching a maximum at about 90 When a poling electric field of 35KV/cm was applied to the sample calcined at 90 and sintered for two hours at 120 Kp attained a maximum value of 0.64 which is in good agreement with the results of other investigators.

Experiments related to nitriding silicon with addition of have provided information on the effects of such inclusion on the phase relationships of Reaction Bonded Silicon Nitride. In the current work specimens containing 0-25wt% Si3N4 which have 55.5wt% 4.5wt% , 40wt% amorphous phase were nitrided for 7-20 hours at 1300-135 The evaluation of nitridation was per-formed by means of -and -phase contents determination in nitrided specimens, In order to observe nitrided region between silicon and silicon nitride scanning electron microscopy was used to study reacted region between silicon and silicon nitride particle. For this purpose semiconductor-grade silicon wafer single crystal was used as a silicon source. The incorporation of small amount of powder is contributed to enhancing the rate of formation of -phase

Hard shaped bodies are made by sintering a cold-pressed compact of a boron carbide compound which contains a densification aid. Titanium diboride and carbon were used as a densification aid in a range of 1% to 10% by weight. The effects of sintering temperature and additives on linear shrinkage porosity hardness bend strength and microstructure were examined. The initial partical size dependence on the sintered density was also discussed.